Car Overheats When AC Is On: Causes, Symptoms, & How To Fix

Have you ever been driving and your car overheats when AC is on? This could be your problem and knowing the causes, symptoms, and how to fix the problem could save you a lot of money on repairs. This blog will break everything down for you and even tell you what you can do to prevent the car from overheating in the first place.

5 Causes Why Your Car Overheats When AC Is On

Poor cooling system

There are a few reasons why your car might overheat when the air conditioning is on. The most common one has to do with the cooling system. If you don’t have enough coolant in your system, your car will overheat more quickly when the AC is on because it’s working harder to cool down the cabin. Another reason might be a problem with the air conditioning compressor. If the compressor is damaged, it won’t be able to circulate the coolant properly, and your car will overheat.

Engine Coolant Sensor Defective

The engine coolant sensor is what tells your car when to turn the AC off so that it doesn’t overheat. If this sensor is defective, it can cause your car to overheat – even when the AC is on. Here’s a quick explanation of why this actually happens:

The engine coolant sensor monitors the temperature of the coolant and sends a signal to the car’s computer. The computer then uses this information to regulate the AC compressor. If the engine coolant sensor is defective, it might not send the correct signal to the computer. As a result, the computer might not turn off the AC compressor even when the coolant is getting too hot. This can cause your car to overheat.

Defective Water Pump

A defective water pump in your car can cause it to overheat when the air conditioning is turned on. Many people don’t know this and often wonder why their car starts to overheat so quickly after turning on the AC. The water pump is responsible for circulating coolant through your engine. When it fails, the coolant isn’t circulated properly and your engine can overheat.

One way to tell if your water pump is failing is if you notice your car’s temperature gauge rising when you turn on the AC. If this happens, you should take your car to a mechanic to have it checked out.

Overloaded AC Compressor

The overloading of an AC compressor can cause your car to overheat when the AC is on. Many people have no idea why this actually happens, but it all comes down to the pressure that is being put on the system. When the AC compressor is overloaded, it causes the refrigerant to work overtime, which in turn causes the engine to work harder. This makes the engine run hot, and eventually, this will cause the car to overheat.

Condenser Fins with Clogging

When your car’s AC is on, clogged condenser fins can cause your car to overheat. Here’s why this happens:
The fins on your car’s condenser help to dissipate heat. When they become clogged with debris, they are not able to do their job as effectively, causing your car to overheat.

6 Symptoms Why Your Car Overheats When AC Is On

There are a few reasons why your car might overheat when you turn on the air conditioning. Here are some symptoms to look out for:

Low coolant levels

A low coolant level is typically a sign that your car is overheating, especially when the air conditioning is turned on. The most common cause of this is a coolant leak, so you’ll want to check for any leaks and repair them as soon as possible. In the meantime, you can try adding more coolant to the reservoir, but be sure to check the level often and top it off as needed.

Faulty radiator cap

A faulty radiator cap is one of the signs that your car might overheat when the AC is turned on. So, what’s the solution?
If you notice that your car’s radiator cap is faulty, one of the best things you can do is to take it to a mechanic and have them take a look at it. They will be able to tell you whether or not the problem is with the radiator cap itself or if there is something else going on with your car that might be causing the overheating issue. In some cases, a simple fix like replacing the radiator cap can solve the problem.

However, if there is something more serious going on, it’s best to leave it to the professionals to figure out and fix


Thermostat problems

If your car overheats when the air conditioner is on, it could be a sign of a thermostat problem. The solution is to have the thermostat replaced.

Electrical issues

If your car overheats when the AC is on, it may be due to an electrical issue. One potential solution is to check the fuse box for any blown fuses. You may also want to check the wiring to see if there are any loose or damaged connections.

Airflow problems

Airflow problems are a sign that your car is overheating when the AC is on. The solution is to have the AC checked and repaired by a professional mechanic.

Compressor problems

Compressor problems are a sign that your car is overheating when the AC is on. The solution is to turn off the AC and let the car cool down.

Step-by-Step Guide To Fix Your Car Overheats When AC Is On

If your car overheats when the AC is on, there are a few things you can do to fix the problem.

First, make sure that your car’s cooling system is working properly. If it isn’t, you may need to flush the system and add new coolant.

Next, check the AC condenser for any blockages. If there are any, you’ll need to clean them out so that air can flow freely through the system.

Finally, inspect the AC compressor for any signs of damage. If it looks like it needs to be replaced, take your car to a mechanic so they can take care of it for you.

Following these steps should help you fix your car’s overheating problem when the AC is on.

Step By Step Guide To Prevent Car Overheats Problem When AC Is On

No one likes getting into a hot car, especially during the summer. But what’s even worse is when your car starts to overheat because you turned on the air conditioning. When it comes to your car, it’s your responsibility to make sure everything is in tip-top shape. After all, you wouldn’t want your car to overheat when you’re out on the road and you need it to get home. So how can you prevent this from happening?

The best thing you can do is be proactive and always keep an eye on the temperature gauge of your car. If it starts to get up near the red line, turn off the air conditioning and open the windows to let some air in. This will help to cool off your engine and prevent it from overheating.

If you’re ever in doubt about your car’s temperature, just pull over to a safe spot and turn off the car. Then wait to see if the engine cools off and the needle drops back down.

  1. Check your coolant levels regularly and top off as needed
  2. Get your car serviced regularly to ensure everything is in working order
  3. Park in the shade whenever possible
  4. Use a sunshade on your windshield when parked
  5. Roll down your windows when first turning on the AC to help cool down the interior of your car faster

If not, contact a mechanic right away to have it checked out. At the end of the day, your car is a major investment, so it’s important that you take


Q: Can an AC cause a car to overheat?

A: Under certain conditions, an AC can cause a car to overheat. If the AC is set to a very low temperature and the car is driven in hot weather, the AC can lower the temperature of the engine too much and cause it to overheat.

Q: What are the signs of a bad AC compressor?

A: There are several signs that your AC compressor may be going bad. If you notice any of the following, it’s time to call a professional for help:

  • Strange noises coming from the compressor
  • The AC unit is cycling on and off more frequently than usual
  • Decreased airflow from the vents
  • Warm air coming from the vents
  • The AC unit is taking longer than usual to cool your home

Q: How much does it cost to fix a car that overheats when the AC is on?

A: If your car overheats when the AC is on, it could be due to a number of different issues. The cost to fix it will depend on the problem, but it could range from a few hundred dollars to a few thousand.


It’s not a great feeling to realize you’re car is overheating. We hope this article has helped you discover some helpful information about car overheating. If you can’t get your car to cool down, we recommend having it looked at by a reliable mechanic. Keep in mind that overheating can be a sign of a bigger problem, so it’s best to get it checked out sooner rather than later. We hope you never have to experience the panic of your car overheating, but if you do, you know what to do. If you want to learn more please visit _ OUR WEBSITE